I. Field of the Invention
This invention pertains to a variable placement interchangeable lamp system and, more particularly, to a variable placement interchangeable lamp system having readily positionable and electrically interconnectable lamps for use on a support member such as a gate crossing arm.
II. Description of the Prior Art
Railroad crossing gates are in wide spread use and are provided with long crossing arms for traffic barriers. The crossing arms are normally upright and are swung to a lowered, horizontal position when an approaching train is detected. The crossing arms of railroad crossing gates are provided with various signal lights which are secured to the crossing arm. Conventionally, three signal lights are used. A first light is disposed at the free end of the crossing arm. The remaining two lights are generally equispaced along the crossing arm. It is conventional that the lights be incorporated into an electrical circuit such that the light at the free end is constantly illuminated when the crossing arm is in its horizontal position. The remaining signal lights are disposed in the electrical circuit such that they are flashing with the two lights alternately flashing off and on.
The environments in which railroad crossing gates are employed are numerous. For example, the crossing gates may be placed adjacent to railroad lines in urban areas where they span streets of widely varying width. Likewise, rural installations also require spans of varying lengths. In addition to these customary settings, railroad crossing arms are found in many industrial settings which also require spans of various lengths.
Due to the indeterminant variety of crossing arm spans which may be required for a crossing gate installation, railroad crossing gates and their set up could not be standardized. For example, the length of the crossing arm could not be determined until the specific site at which the crossing gate was to be installed was known. Once the length of the gate arm was determined, the precise positioning of the signal lights (commonly referred to and hereafter referred to as gate lamps) could then be established. As noted above, the positioning of the gate lamps on the arm is such that the gate lamps are generally equispaced. Since the widths of the traffic lanes are not standardized from application to application, the positioning of the gate lamps on the arm must be done on a case by case basis. As is customary in prior art crossing gates, the gate lamp was secured to a junction box which was mounted on the gate arm either within an interior of the arm or on its exterior. In either event, mounting holes for the junction box would be drilled into the gate arm at each of the desired positions for a gate lamp. With the gate lamps installed, wiring would be run either inside or outside of the gate arm to connect the gate lamps in the appropriate circuitry for two of the lamps to be alternatingly flashing and the end lamp to be constantly illuminated when the arm was in the down position. This would require individual customized electrical work and customized cutting and splicing of wires as well as insuring that the appropriate wire from the circuit led to the appropriate gate lamp.
In light of all the individual manufacturing steps required to fabricate a finished crossing arm for a particular installation, the amount of time and effort required to install a crossing gate is substantial. This is particularly true where much of the installation steps take place in the field. While it would be desirable to standardize the assembly of a crossing arm, the art has not developed such a crossing gate.